Copper alloy, copper alloy plastic working material, component for electronic/electrical device, terminal, bus bar, lead frame, and heat dissipation substrate

ABSTRACT

This copper alloy contains greater than 10 mass ppm and less than 100 mass ppm of Mg, with a balance being Cu and inevitable impurities, which comprise: 10 mass ppm or less of S, 10 mass ppm or less of P, 5 mass ppm or less of Se, 5 mass ppm or less of Te, 5 mass ppm or less of Sb, 5 mass ppm or less of Bi, and 5 mass ppm or less of As. The total amount of S, P, Se, Te, Sb, Bi, and As is 30 mass ppm or less. The mass ratio [Mg]/[S+P+Se+Te+Sb+Bi+As] is 0.6 to 50, an electrical conductivity is 97% IACS or greater. The half-softening temperature ratio TLD/TTD is greater than 0.95 and less than 1.08. The half-softening temperature TLD is 210° C. or higher.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a U.S. National Phase Application under 35 U.S.C. §371 of International Patent Application No. PCT/JP2021/024723 filed onJun. 30, 2021 and claims the benefit of priority to Japanese PatentApplications No. 2020-112695 filed on Jun. 30, 2020, No. 2020-112927filed on Jun. 30, 2020 and No. 2020-181736 filed on Oct. 29, 2020, thecontents of all of which are incorporated herein by reference in theirentireties. The International Application was published in Japanese onJan. 6, 2022 as International Publication No. WO/2022/004779 under PCTArticle 21(2).

FIELD OF THE INVENTION

The present invention relates to a copper alloy suitable for a componentfor electronic/electrical devices such as a terminal, a bus bar, a leadframe, a heat dissipation substrate, and the like; a plastically-workedcopper alloy material; a component for electronic/electrical devices; aterminal; a bus bar; a lead frame; and a heat dissipation substrate,which include this copper alloy.

BACKGROUND OF THE INVENTION

In the related art, as a component for electronic/electrical devicessuch as a terminal, a bus bar, a lead frame, or a heat dissipationsubstrate, copper or a copper alloy with excellent electricalconductivity has been used.

With an increase in current of electronic devices and electricaldevices, in order to reduce the current density and diffuse heat due toJoule heat generation, a pure copper material such as oxygen-free copperwith excellent electrical conductivity is applied to a component forelectronic/electrical devices used for such electronic devices andelectrical devices.

In recent years, with an increase in the amount of current used for acomponent for electronic/electrical devices, the thickness of a usedcopper material has increased. With heat generation in a case ofelectrical conduction and an increase in temperature in a useenvironment, there is a demand for a copper material with excellent heatresistance indicating that the hardness is unlikely to decrease at ahigh temperature. Further, in a large-sized terminal, a bus bar, and alead frame that are loaded with a high current, it is necessary to use arolled material with less anisotropy. However, a pure copper materialhas a problem that the material cannot be used in a high-temperatureenvironment due to insufficient heat resistance indicating that thehardness is unlikely to decrease at a high temperature.

Therefore, Japanese Unexamined Patent Application, First Publication No.2016-056414 discloses a rolled copper plate containing 0.005% by mass orgreater and less than 0.1% by mass of Mg.

The rolled copper plate described in Japanese Unexamined PatentApplication, First Publication No. 2016-056414 has a compositionincluding 0.005% by mass or greater and less than 0.1% by mass of Mgwith the balance being Cu and inevitable impurities, and thus the stressrelaxation resistance can be improved without greatly decreasing theelectrical conductivity by dissolving Mg in a Cu matrix.

Meanwhile, recently, a copper material constituting the component forelectronic/electrical devices is required to further improve theelectrical conductivity in order to use the copper material forapplications where the pure copper material has been used, and in orderto sufficiently suppress heat generation in a case where a high currentflows. In the copper alloy described in Japanese Unexamined PatentApplication, First Publication No. 2016-056414, since the stressrelaxation resistance is improved by adding a solute element, theelectrical conductivity thereof is inferior to that of pure copper.Therefore, development of a material with higher electrical conductivityand high heat resistance which is capable of dealing with heatgeneration due to an increase in current has been desired.

Further, since the above-described component for electronic/electricaldevices is likely to be used in a high-temperature environment such asan engine room, the copper material constituting the component forelectronic/electrical devices is required to improve the heat resistancemore than before.

Further, there is a demand for a copper alloy with less anisotropy inheat resistance in order to stably use a component forelectronic/electrical devices in various shapes.

PRIOR ART DOCUMENTS Patent Document

Patent Document 1: Japanese Unexamined Patent Application, FirstPublication No. 2016-056414

Problems to be Solved by the Invention

The present invention has been made in view of the above-describedcircumstances, and an object thereof is to provide a copper alloy, aplastically-worked copper alloy material, a component forelectronic/electrical devices, a terminal, a bus bar, a lead frame, anda heat dissipation substrate, which have high electrical conductivity,excellent heat resistance, and less anisotropy in heat resistance.

SUMMARY OF THE INVENTION Solutions for Solving the Problems

As a result of intensive research conducted by the present inventors inorder to achieve the above-described object, it was found that additionof a small amount of Mg and regulation of the amount of an elementgenerating a compound with Mg are required to achieve the balancebetween the high electrical conductivity and the excellent heatresistance. That is, it was found that the electrical conductivity andthe heat resistance can be further improved more than before in awell-balanced manner by regulating the amount of an element generating acompound with Mg and allowing the small amount of Mg that has been addedto be present in the copper alloy in an appropriate form.

The present invention has been made based on the above-describedfindings. According to an aspect of the present invention, there isprovided a copper alloy having a composition including Mg in an amountof greater than 10 mass ppm and less than 100 mass ppm, with a balancebeing Cu and inevitable impurities, in which among the inevitableimpurities, an amount of S is 10 mass ppm or less, an amount of P is 10mass ppm or less, an amount of Se is 5 mass ppm or less, an amount of Teis 5 mass ppm or less, an amount of Sb is 5 mass ppm or less, an amountof Bi is 5 mass ppm or less, an amount of As is 5 mass ppm or less, atotal amount of S, P, Se, Te, Sb, Bi, and As is 30 mass ppm or less,when the amount of Mg is represented as [Mg] and the total amount of S,P, Se, Te, Sb, Bi, and As is represented as [S+P+Se+Te+Sb+Bi+As], a massratio thereof, [Mg]/[S+P+Se+Te+Sb+Bi+As] is 0.6 or greater and 50 orless, an electrical conductivity is 97% IACS or greater, ahalf-softening temperature ratio T_(LD)/T_(TD) calculated from ahalf-softening temperature T_(LD) obtained by performing a tensile testin a direction parallel to a rolling direction and a half-softeningtemperature T_(TD) obtained by performing a tensile test in a directiontransverse to the rolling direction is greater than 0.95 and less than1.08, and the half-softening temperature T_(LD) obtained by performingthe tensile test in a direction parallel to a rolling direction is 210°C. or higher.

In the aspect of the present invention, the half-softening temperatureratio T_(LD)/T_(TD) is a temperature ratio in kelvin.

According to the copper alloy with the above-described configuration,since the amount of Mg and the amounts of S, P, Se, Te, Sb, Bi, and As,which are elements generating compounds with Mg, are defined asdescribed above, the heat resistance can be improved without greatlydecreasing the electrical conductivity by dissolving a small amount ofadded Mg in a Cu matrix. Specifically, the electrical conductivity canbe set to 97% IACS or greater, and the half-softening temperature T_(LD)obtained by performing the tensile test in a direction parallel to arolling direction can be set to 210° C. or higher.

Further, since the half-softening temperature ratio T_(LD)/T_(TD)calculated from the half-softening temperature T_(LD) obtained byperforming the tensile test in a direction parallel to a rollingdirection and the half-softening temperature T_(TD) obtained byperforming a tensile test in a direction transverse to the rollingdirection is set to be in a range of greater than 0.95 and less than1.08, the anisotropy in heat resistance is small and the strength in ahigh-temperature environment can be sufficiently ensured even in a casewhere the heat resistance is required in both the direction parallel tothe rolling direction and the direction transverse to the rollingdirection, such as a terminal or a bus bar for a high current.

Further, in the copper alloy according to the aspect of the presentinvention, it is preferable that an amount of Ag is 5 mass ppm orgreater and 20 mass ppm or less.

In this case, since the amount of Ag is in the above-described range, Agsegregates in the vicinity of grain boundaries, grain boundary diffusionis suppressed, and the heat resistance can be improved.

Further, in the copper alloy according to the aspect of the presentinvention, it is preferable that an area ratio of crystals having acrystal orientation which is 10° or less with respect to Brassorientation {110} <112> is 30% or less.

In this case, since the area ratio of crystals having a crystalorientation which is 10° or less with respect to Brass orientation {110}<112> is limited to 30% or less, the anisotropy in heat resistance canbe suppressed. In addition, it is possible to suppress the strength in adirection transverse to the rolling direction from being preferentiallyincreased and to suppress occurrence of anisotropy in strength.

Further, in the copper alloy according to the aspect of the presentinvention, it is preferable that a strength ratio TS_(TD)/TS_(LD)calculated from a tensile strength TS_(TD) in a case of performing atensile test in the direction transverse to the rolling direction and atensile strength TS_(LD) in a case of performing a tensile test in thedirection parallel to the rolling direction is greater than 0.93 andless than 1.10 and that a tensile strength TS_(LD) in a case ofperforming a tensile test in the direction parallel to the rollingdirection is 200 MPa or greater.

In this case, since the strength ratio TS_(TD)/TS_(LD) calculated fromthe tensile strength TS_(TD) in a case of performing the tensile test inthe direction transverse to the rolling direction and the tensilestrength TS_(LD) in a case of performing the tensile test in thedirection parallel to the rolling direction is set to be in a range ofgreater than 0.93 and less than 1.10, the anisotropy in strength issmall and the strength can be sufficiently ensured even in a case wherethe strength is required in both the direction parallel to the rollingdirection and the direction transverse to the rolling direction, such asa terminal or a bus bar for a high current.

Further, since the tensile strength TS_(LD) in a case of performing thetensile test in the direction parallel to the rolling direction is setto 200 MPa or greater, the strength is sufficiently excellent.

A plastically-worked copper alloy material according to one aspect ofthe present invention includes the copper alloy described above.

According to the plastically-worked copper alloy material with theabove-described configuration, since the plastically-worked copper alloymaterial includes the above-described copper alloy, theplastically-worked copper alloy material has excellent electricalconductivity, excellent heat resistance, and small anisotropy in heatresistance, and thus is particularly suitable as a material of acomponent for electronic/electrical devices, such as a terminal, a busbar, a lead frame, or a heat dissipation substrate, used forhigh-current applications in a high-temperature environment.

The plastically-worked copper alloy material according to the aspect ofthe present invention may be a rolled plate having a thickness of 0.1 mmor greater and 10 mm or less.

In this case, since the plastically-worked copper alloy material is arolled plate having a thickness of 0.1 mm or greater and 10 mm or less,a component for electronic/electrical devices, such as a terminal, a busbar, a lead frame, or a heat dissipation substrate, can be molded bysubjecting the plastically-worked copper alloy material (rolled plate)to punching or bending.

In regard to the plastically-worked copper alloy material according tothe aspect of the present invention, it is preferable that theplastically-worked copper alloy material includes a Sn plating layer oran Ag plating layer on a surface thereof.

That is, it is preferable that the plastically-worked copper alloymaterial according to the aspect of the present invention includes amain body of the plastically-worked copper alloy material and a Snplating layer or Ag plating layer provided on the surface of the mainbody. The main body may be a rolled plate consisting of the copper alloydescribed above and having a thickness of 0.1 mm or greater and 10 mm orless. In this case, since the plastically-worked copper alloy materialincludes a Sn plating layer or an Ag plating layer on the surfacethereof, the plastically-worked copper alloy material is particularlysuitable as a material of a component for electronic/electrical devices,such as a terminal, a bus bar, a lead frame, or a heat dissipationsubstrate. Further, according to one aspect of the present invention,the concept of “Sn plating” includes pure Sn plating or Sn alloy platingand the concept of “Ag plating” includes pure Ag plating or Ag alloyplating.

A component for electronic/electrical devices according to one aspect ofthe present invention includes the plastically-worked copper alloymaterial described above. Further, examples of the component forelectronic/electrical devices according to the aspect of the presentinvention include a terminal, a bus bar, a lead frame, and a heatdissipation substrate.

The component for electronic/electrical devices with the above-describedconfiguration is produced by using the above-describedplastically-worked copper alloy material, and thus the component canexhibit excellent characteristics even in a case of being used forhigh-current applications in a high-temperature environment.

A terminal according to one aspect of the present invention includes theplastically-worked copper alloy material described above.

The terminal with the above-described configuration is produced by usingthe plastically-worked copper alloy material described above, and thusthe terminal can exhibit excellent characteristics even in a case ofbeing used for high-current applications in a high-temperatureenvironment.

A bus bar according to one aspect of the present invention includes theplastically-worked copper alloy material described above.

The bus bar with the above-described configuration is produced by usingthe plastically-worked copper alloy material described above, and thusthe bus bar can exhibit excellent characteristics even in a case ofbeing used for high-current applications in a high-temperatureenvironment.

A lead frame according to one aspect of the present invention includesthe plastically-worked copper alloy material described above.

The lead frame with the above-described configuration is produced byusing the plastically-worked copper alloy material described above, andthus the lead frame can exhibit excellent characteristics even in a caseof being used for high-current applications in a high-temperatureenvironment.

A heat dissipation substrate according to one aspect of the presentinvention is prepared by using the copper alloy described above.

The heat dissipation substrate with the above-described configuration isprepared by using the copper alloy described above, and thus the heatdissipation substrate can exhibit excellent characteristics even in acase of being used for high-current applications in a high-temperatureenvironment.

Effects of Invention

According to the aspect of the present invention, it is possible toprovide a copper alloy, a plastically-worked copper alloy material, acomponent for electronic/electrical devices, a terminal, a bus bar, alead frame, and a heat dissipation substrate, which have high electricalconductivity, excellent heat resistance, and less anisotropy in heatresistance.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE is a flow chart showing a method for producing a copper alloyaccording to the present embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a copper alloy according to an embodiment of the presentinvention will be described.

The copper alloy according to the present embodiment is a copper alloywhich has a composition including Mg in an amount of greater than 10mass ppm and less than 100 mass ppm, with a balance being Cu andinevitable impurities, in which among the inevitable impurities, theamount of S is 10 mass ppm or less, the amount of P is 10 mass ppm orless, the amount of Se is 5 mass ppm or less, the amount of Te is 5 massppm or less, the amount of Sb is 5 mass ppm or less, the amount of Bi is5 mass ppm or less, and the amount of As is 5 mass ppm or less, and thetotal amount of S, P, Se, Te, Sb, Bi, and As is 30 mass ppm or less.

Further, when the amount of Mg is represented as [Mg] and the totalamount of S, P, Se, Te, Sb, Bi, and As is represented as[S+P+Se+Te+Sb+Bi+As], the mass ratio thereof, [Mg]/[S+P+Se+Te+Sb+Bi+As]is 0.6 or greater and 50 or less.

Further, in the copper alloy according to the present embodiment, theamount of Ag may be 5 mass ppm or greater and 20 mass ppm or less.

Further, the copper alloy according to the present embodiment has anelectrical conductivity of 97% IACS or greater.

Furthermore, in the copper alloy according to the present embodiment,the half-softening temperature T_(LD) obtained by performing the tensiletest in a direction parallel to a rolling direction is set to 210° C. orhigher.

In the copper alloy according to the present embodiment, thehalf-softening temperature ratio T_(LD)/T_(TD) calculated from thehalf-softening temperature T_(LD) obtained by performing the tensiletest in a direction parallel to a rolling direction and thehalf-softening temperature T_(TD) obtained by performing a tensile testin a direction transverse to the rolling direction is set to be in arange of greater than 0.95 and less than 1.08.

Further, the half-softening temperature ratio T_(LD)/T_(TD) in thepresent embodiment is a temperature ratio in kelvin.

Further, in the copper alloy according to the present embodiment, it ispreferable that the area ratio of crystals having a crystal orientationwhich is 10° or less with respect to Brass orientation {110} <112> isset to 30% or less.

Further, in the copper alloy according to the present embodiment, it ispreferable that the strength ratio TS_(TD)/TS_(LD) calculated from thetensile strength TS_(TD) in a case of performing the tensile test in thedirection transverse to the rolling direction and the tensile strengthTS_(LD) in a case of performing the tensile test in the directionparallel to the rolling direction is set to be in a range of greaterthan 0.93 and less than 1.10.

Further, in the copper alloy according to the present embodiment, it ispreferable that the tensile strength TS_(LD) in a case of performing thetensile test in the direction parallel to the rolling direction is 200MPa or greater.

In the copper alloy according to the present embodiment, the reasons forspecifying the component composition, the texture, and variouscharacteristics as described above will be described.

(Mg)

Mg is an element having an effect of improving the strength and the heatresistance without greatly decreasing the electrical conductivity bybeing dissolved in the Cu matrix.

In a case where the amount of Mg is 10 mass ppm or less, there is aconcern that the effect may not be sufficiently exhibited. On thecontrary, in a case where the amount of Mg is 100 mass ppm or greater,the electrical conductivity may be decreased.

As described above, in the present embodiment, the amount of Mg is setto be in a range of greater than 10 mass ppm and less than 100 mass ppm.

In order to further improve the heat resistance, the lower limit of theamount of Mg is set to preferably 20 mass ppm or greater, morepreferably 30 mass ppm or greater, and still more preferably 40 mass ppmor greater.

Further, in order to further increase the electrical conductivity, theupper limit of the amount of Mg is preferably less than 90 mass ppm. Ina case where the electrical conductivity is increased, the upper limitof the amount of Mg is more preferably less than 80 mass ppm and morepreferably less than 70 mass ppm in order to achieve the balance betweenthe electrical conductivity, the heat resistance, and the stressrelaxation characteristic.

(S, P, Se, Te, Sb, Bi, and As)

The elements such as S, P, Se, Te, Sb, Bi, and As described above areelements that are typically easily mixed into a copper alloy. Theseelements are likely to react with Mg to form a compound, and thus mayreduce the solid-solution effect of a small amount of added Mg.Therefore, the amounts of these elements are required to be strictlycontrolled.

Therefore, in the present embodiment, the amount of S is limited to 10mass ppm or less, the amount of P is limited to 10 mass ppm or less, theamount of Se is limited to 5 mass ppm or less, the amount of Te islimited to 5 mass ppm or less, the amount of Sb is limited to 5 mass ppmor less, the amount of Bi is limited to 5 mass ppm or less, and theamount of As is limited to 5 mass ppm or less.

Further, the total amount of S, P, Se, Te, Sb, Bi, and As is limited to30 mass ppm or less.

The lower limits of the amounts of the above-described elements are notparticularly limited, but the amount of each of S, P, Sb, Bi, and As ispreferably 0.1 mass ppm or greater and more preferably 0.2 mass ppm orgreater from the viewpoint that the production cost is increased inorder to greatly reduce the amounts of the above-described elements. Theamount of Se is preferably 0.05 mass ppm or greater and more preferably0.1 mass ppm or greater. The amount of Te is preferably 0.01 mass ppm orgreater and more preferably 0.05 mass ppm or greater.

The lower limit of the total amount of S, P, Se, Te, Sb, Bi, and As isnot particularly limited, but the total amount of S, P, Se, Te, Sb, Bi,and As is preferably 0.6 mass ppm or greater and more preferably 1.0mass ppm or greater from the viewpoint that the production cost isincreased in order to greatly reduce the total amount thereof.

Further, the amount of S is preferably 9 mass ppm or less and morepreferably 8 mass ppm or less.

The amount of P is preferably 6 mass ppm or less and more preferably 3mass ppm or less.

The amount of Se is preferably 4 mass ppm or less and more preferably 2mass ppm or less.

The amount of Te is preferably 4 mass ppm or less and more preferably 2mass ppm or less.

The amount of Sb is preferably 4 mass ppm or less and more preferably 2mass ppm or less.

The amount of Bi is preferably 4 mass ppm or less and more preferably 2mass ppm or less.

The amount of As is preferably 4 mass ppm or less and more preferably 2mass ppm or less.

Further, the total amount of S, P, Se, Te, Sb, Bi, and As is preferably24 mass ppm or less and more preferably 18 mass ppm or less.

([Mg]/[S+P+Se+Te+Sb+Bi+As])

As described above, since elements such as S, P, Se, Te, Sb, Bi, and Aseasily react with Mg to form compounds, the existence form of Mg iscontrolled by defining the ratio between the amount of Mg and the totalamount of S, P, Se, Te, Sb, Bi, and As in the present embodiment.

When the amount of Mg is represented as [Mg] and the total amount of S,P, Se, Te, Sb, Bi, and As is represented as [S+P+Se+Te+Sb+Bi+As], in acase where the mass ratio thereof, [Mg]/[S+P+Se+Te+Sb+Bi+As] is greaterthan 50, Mg is excessively present in copper in a solid solution state,and thus the electrical conductivity may be decreased. On the contrary,in a case where the mass ratio thereof, [Mg]/[S+P+Se+Te+Sb+Bi+As] isless than 0.6, Mg is not sufficiently dissolved in copper, and thus theheat resistance may not be sufficiently improved.

Therefore, in the present embodiment, the mass ratio[Mg]/[S+P+Se+Te+Sb+Bi+As] is set to be in a range of 0.6 or greater and50 or less.

In addition, the amount of each element in the above-described massratio is in units of mass ppm.

In order to further suppress a decrease in electrical conductivity, theupper limit of the mass ratio [Mg]/[S+P+Se+Te+Sb+Bi+As] is preferably 35or less and more preferably 25 or less.

Further, in order to further improve the heat resistance, the lowerlimit of the mass ratio [Mg]/[S+P+Se+Te+Sb+Bi+As] is set to preferably0.8 or greater and more preferably 1.0 or greater.

(Ag: 5 Mass ppm or Greater and 20 Mass ppm or Less)

Ag is unlikely to be dissolved in the Cu matrix in a temperature rangeof 250° C. or lower, in which typical electronic/electrical devices areused. Therefore, a small amount of Ag added to copper segregates in thevicinity of grain boundaries. In this manner, since movement of atoms atgrain boundaries is hindered and grain boundary diffusion is suppressed,the heat resistance is improved.

In a case where the amount of Ag is 5 mass ppm or greater, the effectscan be sufficiently exhibited. On the contrary, in a case where theamount of Ag is 20 mass ppm or less, the electrical conductivity can beensured and an increase in production cost can be suppressed.

As described above, in the present embodiment, the amount of Ag is setto be in a range of 5 mass ppm or greater and 20 mass ppm or less.

In order to further improve the heat resistance, the lower limit of theamount of Ag is set to preferably 6 mass ppm or greater, more preferably7 mass ppm or greater, and still more preferably 8 mass ppm or greater.Further, in order to reliably suppress a decrease in the electricalconductivity and an increase in cost, the upper limit of the amount ofAg is set to preferably 18 mass ppm or less, more preferably 16 mass ppmor less, and still more preferably 14 mass ppm or less.

Further, in a case where Ag is not intentionally included and theinevitable impurities include Ag, the amount of Ag may be less than 5mass ppm.

(Other Inevitable Impurities)

Examples of other inevitable impurities other than the above-describedelements include Al, B, Ba, Be, Ca, Cd, Cr, Sc, rare earth elements, V,Nb, Ta, Mo, Ni, W, Mn, Re, Ru, Sr, Ti, Os, Co, Rh, Ir, Pb, Pd, Pt, Au,Zn, Zr, Hf, Hg, Ga, In, Ge, Y, Tl, N, Si, Sn, and Li. The copper alloymay contain inevitable impurities within a range not affecting thecharacteristics.

Since there is a concern that the electrical conductivity is decreased,it is preferable that the amount of the inevitable impurities isreduced.

(Half-Softening Temperature Ratio T_(LD)/T_(TD): Greater Than 0.95 andLess Than 1.08)

In the present embodiment, since the half-softening temperature ratioT_(LD)/T_(TD) calculated from the half-softening temperature T_(LD)obtained by performing the tensile test in a direction parallel to arolling direction and the half-softening temperature T_(TD) obtained byperforming a tensile test in a direction transverse to the rollingdirection is set to be in a range of greater than 0.95 and less than1.08, the anisotropy in heat resistance is small and the strength in ahigh-temperature environment can be sufficiently ensured in both thedirection parallel to the rolling direction and the direction transverseto the rolling direction.

In order to reliably exhibit the above-described effect, the lower limitof the half-softening temperature ratio T_(LD)/T_(TD) is set topreferably 0.97 or greater and more preferably 0.98 or greater. On thecontrary, the upper limit of the half-softening temperature ratioT_(LD)/T_(TD) is set to preferably 1.06 or less and more preferably 1.04or less.

(Electrical Conductivity: 97% IACS or Greater)

In the copper alloy according to the present embodiment, the electricalconductivity is 97% IACS or greater. The heat generation in a case ofelectrical conduction is suppressed by setting the electricalconductivity to 97% IACS or greater so that the copper alloy can besatisfactorily used as a component for electronic/electrical devicessuch as a terminal, a bus bar, a lead frame, or a heat dissipationsubstrate as a substitute to a pure copper material.

The electrical conductivity is preferably 97.5% IACS or greater, morepreferably 98.0% IACS or greater, still more preferably 98.5% IACS orgreater, and even still more preferably 99.0% IACS or greater.

The upper limit of the electrical conductivity is not particularlylimited, but is preferably 103.0% IACS or less.

(Half-Softening Temperature T_(LD) Obtained by Performing Tensile Testin Direction Parallel to Rolling Direction: 210° C. or Higher)

In the copper alloy according to the present embodiment, in a case wherethe half-softening temperature T_(LD) obtained by performing the tensiletest in a direction parallel to the rolling direction is high, recoveryin the copper material and softening phenomenon due to recrystallizationare unlikely to occur even at a high temperature; and therefore, thecopper alloy can be applied to an electric conductive member used in ahigh-temperature environment.

Therefore, in the present embodiment, the half-softening temperatureT_(LD) obtained by performing the tensile test in a direction parallelto the rolling direction is set to 210° C. or higher.

Further, the half-softening temperature T_(LD) obtained by performingthe tensile test in a direction parallel to the rolling direction ismore preferably 225° C. or higher, still more preferably 250° C. orhigher, and even still more preferably 275° C. or higher.

The upper limit of the half-softening temperature T_(LD) is notparticularly limited, but is preferably 600° C. or lower.

(Strength Ratio TS_(TD)/TS_(LD) : Greater Than 0.93 and Less Than 1.10)

In a case where the strength ratio TS_(TD)/TS_(LD) calculated from thetensile strength TS_(TD) in a case of performing the tensile test in thedirection transverse to the rolling direction and the tensile strengthTS_(LD) in a case of performing the tensile test in the directionparallel to the rolling direction is set to be in a range of greaterthan 0.93 and less than 1.10, the anisotropy in strength is small andthe strength is sufficiently ensured even in a case where the strengthis required in both the LD direction (direction parallel to the rollingdirection) and the TD direction (direction transverse to the rollingdirection), such as a terminal or a bus bar for a high current.

In order to reliably exhibit the above-described effect, the lower limitof the strength ratio TS_(TD)/TS_(LD) is set to more preferably 0.95 orgreater and still more preferably 0.98 or greater. Further, the upperlimit of the strength ratio TS_(TD)/TS_(LD) is set to more preferably1.08 or less and still more preferably 1.06 or less.

(Tensile Strength TS_(LD) in Direction Parallel to Rolling Direction:200 MPa or Greater)

In the copper alloy according to the present embodiment, in a case wherethe tensile strength TS_(LD) in the direction parallel to the rollingdirection is 200 MPa or greater, the copper alloy is particularlysuitable as a material of a component for electronic/electrical devicessuch as a terminal, a bus bar, or a lead frame. Particularly, the upperlimit of the tensile strength TS_(LD) in the direction parallel to therolling direction is not specified, but it is preferable that thetensile strength TS_(LD) is set to 500 MPa or less in order to avoid adecrease in productivity due to a winding habit of coil in a case wherea coiled strip material is used.

Further, the lower limit of the tensile strength TS_(LD) in thedirection parallel to the rolling direction is more preferably 275 MPaor greater and still more preferably 300 MPa or greater.

(Brass Orientation {110} <112>: 30% or Less)

As the Brass orientation increases, the strength in the directiontransverse to the rolling direction increases. Therefore, in order tosuppress anisotropy in strength, it is preferable that the area ratio ofcrystals having a crystal orientation which is 10° or less with respectto Brass orientation {110} <112> is set to 30% or less.

In order to further suppress anisotropy in strength, the area ratio ofcrystals having a crystal orientation which is 10° or less with respectto Brass orientation {110} <112> is set to preferably 20% or less andmore preferably 10% or less.

Meanwhile, in a case where the ratio of the Brass orientation isextremely small, since the strength in the direction transverse to therolling direction is extremely decreased and thus required strength maynot be ensured, the lower limit of the area ratio of crystals having acrystal orientation which is 10° or less with respect to Brassorientation {110} <112> is preferably 0.5% or greater, more preferably1% or greater, and most preferably 1.5% or greater.

Next, a method for producing the copper alloy according to the presentembodiment with such a configuration will be described with reference tothe flow chart shown in the drawing.

(Melting and Casting Step S01)

First, the above-described elements are added to molten copper obtainedby melting the copper raw material to adjust components; and thereby, amolten copper alloy is produced. Further, a single element, a basealloy, or the like can be used for addition of various elements. Inaddition, raw materials containing the above-described elements may bemelted together with the copper raw material. Further, a recycledmaterial or a scrap material of the copper alloy of the presentembodiment may be used.

As the copper raw material, so-called 4N Cu having a purity of 99.99% bymass or greater or so-called 5N Cu having a purity of 99.999% by mass orgreater is preferably used.

During melting, in order to suppress oxidation of Mg and to reduce thehydrogen concentration, it is preferable that atmosphere-controlledmelting is carried out in an atmosphere using an inert gas atmosphere(for example, Ar gas) in which the vapor pressure of H₂O is low and theholding time for the melting is set to the minimum.

Then, the molten copper alloy in which the components have been adjustedis poured into a mold to produce an ingot. In consideration of massproduction, it is preferable to use a continuous casting method or asemi-continuous casting method.

(Homogenizing/Solutionizing Step S02)

Next, a heat treatment is performed for homogenization andsolutionization of the obtained ingot. An intermetallic compound or thelike containing Cu and Mg as main components may be present inside theingot, and the intermetallic compound is generated by segregation andconcentration of Mg in the solidification process. Therefore, in orderto eliminate or reduce the segregated elements and the intermetalliccompound, a heat treatment of heating the ingot to 300° C. or higher and1080° C. or lower is performed. In this manner, Mg is uniformly diffusedin the ingot or Mg is dissolved in the matrix. In addition, it ispreferable that the homogenizing/solutionizing step S02 is performed ina non-oxidizing or reducing atmosphere.

In a case where the heating temperature is lower than 300° C., thesolutionization may be incomplete, and a large amount of theintermetallic compound containing Cu and Mg as main components mayremain in the matrix. On the contrary, in a case where the heatingtemperature is higher than 1080° C., a part of the copper materialserves a liquid phase, and thus the texture and the surface state may benon-uniform. Therefore, the heating temperature is set to be in a rangeof 300° C. or higher and 1080° C. or lower.

Further, hot working may be performed after the above-describedhomogenizing/solutionizing step S02 in order to improve the efficiencyof rough working and homogenize the texture described below. In thiscase, the working method is not particularly limited, and for example,rolling, drawing, extruding, groove rolling, forging, and pressing canbe employed. Further, it is preferable that the hot working temperatureis set to be in a range of 300° C. or higher and 1080° C. or lower.

(Rough Working Step S03)

In order to work into a predetermined shape, rough working is performed.Further, the temperature conditions for this rough working step S03 arenot particularly limited, but the working temperature is set to bepreferably in a range of −200° C. to 200° C., in which cold working orwarm working (for example, rolling) is carried out, and particularlypreferably room temperature from the viewpoint of suppressingrecrystallization or improving the dimensional accuracy. The workingrate is preferably 20% or greater and more preferably 30% or greater.Further, the working method is not particularly limited, and forexample, rolling, drawing, extruding, groove rolling, forging, andpressing can be employed.

(Intermediate Heat Treatment Step S04)

After the rough working step S03, a heat treatment is performed forsoftening to improve the workability or for obtaining arecrystallization structure. Further, the intermediate heat treatmentstep S04 and the finish working step S05 described below may berepeated.

Since this intermediate heat treatment step S04 is substantially thefinal recrystallization heat treatment, the crystal grain size of therecrystallization structure obtained in this step is approximately thesame as the final crystal grain size. Therefore, in the intermediateheat treatment step S04, it is preferable that the heat treatmentconditions are appropriately selected such that the average crystalgrain size is set to 5 μm or greater. For example, it is preferable tohold for approximately 1 second to 120 seconds in a case of atemperature of 700° C.

(Finish Working Step S05)

In order to work the copper material after the intermediate heattreatment step S04 into a predetermined shape, finish working isperformed. Further, the temperature conditions in this finish workingstep S05 are not particularly limited, but the working temperature isset to be preferably in a range of −200° C. to 200° C., in which coldworking or warm working is carried out, and particularly preferably roomtemperature from the viewpoint of suppressing recrystallization duringthe working or suppressing softening.

Further, the working rate is appropriately selected such that the shapeof the copper material is close to the final shape, but it is preferablethat the working rate is set to 5% or greater in order to obtain workhardening or to increase the Brass orientation ratio which is the rolledtexture so that the strength is improved in the finish working step S05.In order to further improve the strength, the working rate is set tomore preferably 10% or greater and still more preferably 15% or greater.

Further, in order to suppress excessively orienting to the Brassorientation, the working rate is set to preferably 75% or less and morepreferably 70% or less.

Further, the working method is not particularly limited, and forexample, rolling, drawing, extruding, groove rolling, forging, andpressing can be employed.

(Mechanical Surface Treatment Step S06)

After the finish working step S05, a mechanical surface treatment isperformed. The mechanical surface treatment is a treatment ofisotropically applying a compressive stress to the vicinity of thesurface after a desired shape is almost obtained, and has an effect ofdecreasing the anisotropy in heat resistance and strength.

As the mechanical surface treatment, various methods, which have beentypically used, such as a shot peening treatment, a blasting treatment,a lapping treatment, a polishing treatment, buffing, grinder polishing,sandpaper polishing, a tension leveler treatment, and light rolling witha low rolling reduction ratio per pass (light rolling is repeatedlyperformed three times or more by setting the rolling reduction ratio perpass to 1% to 10%) can be used.

Further, the heat resistance is greatly improved by applying thismechanical surface treatment to the copper alloy to which Mg has beenadded.

(Finish Heat Treatment Step S07)

Next, a finish heat treatment may be performed on the plastically-workedmaterial obtained by the mechanical surface treatment step S06 in orderto remove segregation of contained elements to grain boundaries and toremove residual strain.

It is preferable that the heat treatment temperature is set to be in arange of 100° C. or greater and 500° C. or lower. Further, in thisfinish heat treatment step S07, it is necessary to set heat treatmentconditions in order to avoid a large decrease in strength due torecrystallization. For example, it is preferable to hold at 450° C. forapproximately 0.1 to 10 seconds and preferable to hold at 250° C. for 1minute to 100 hours. It is preferable that the heat treatment isperformed in a non-oxidizing atmosphere or a reducing atmosphere. Amethod of performing the heat treatment is not particularly limited, butit is preferable that the heat treatment is performed using a continuousannealing furnace for a short period of time from the viewpoint of theeffect of reducing the production cost.

Further, the finish working step S05, the mechanical surface treatmentstep S06, and the finish heat treatment step S07 may be repeated.

In this manner, the copper alloy (plastically-worked copper alloymaterial) according to the present embodiment is produced. Further, theplastically-worked copper alloy material produced by rolling is referredto as a rolled copper alloy plate.

In a case where the plate thickness of the plastically-worked copperalloy material (rolled copper alloy plate) is set to 0.1 mm or greater,the plastically-worked copper alloy material is suitable for use as aconductor for high-current applications. Further, in a case where theplate thickness of the plastically-worked copper alloy material is setto 10.0 mm or less, an increase in the load of a press machine can besuppressed, the productivity per unit time can be ensured, and thus theproduction cost can be reduced.

Therefore, it is preferable that the plate thickness of theplastically-worked copper alloy material (rolled copper alloy plate) isset to be in a range of 0.1 mm or greater and 10.0 mm or less.

The lower limit of the plate thickness of the plastically-worked copperalloy material (rolled copper alloy plate) is set to preferably 0.5 mmor greater and more preferably 1.0 mm or greater. On the contrary, theupper limit of the plate thickness of the plastically-worked copperalloy material (rolled copper alloy plate) is set to preferably lessthan 9.0 mm and more preferably less than 8.0 mm

In the copper alloy according to the present embodiment with theabove-described configuration, since the amount of Mg is set to be in arange of greater than 10 mass ppm and less than 100 mass ppm, and theamount of S is set to 10 mass ppm or less, the amount of P is set to 10mass ppm or less, the amount of Se is set to 5 mass ppm or less, theamount of Te is set to 5 mass ppm or less, the amount of Sb is set to 5mass ppm or less, the amount of Bi is set to 5 mass ppm or less, theamount of As is set to 5 mass ppm or less, and the total amount of S, P,Se, Te, Sb, Bi, and As, which are the elements generating compounds withMg, is limited to 30 mass ppm or less, a small amount of added Mg can bedissolved in the Cu matrix, and the heat resistance can be improvedwithout greatly decreasing the electrical conductivity.

Further, when the amount of Mg is represented as [Mg] and the totalamount of S, P, Se, Te, Sb, Bi, and As is represented as[S+P+Se+Te+Sb+Bi+As], since the mass ratio thereof[Mg]/[S+P+Se+Te+Sb+Bi+As] is set to be in a range of 0.6 or greater and50 or less, the heat resistance can be sufficiently improved withoutdecreasing electrical conductivity due to the dissolving of excessamount of Mg.

Therefore, according to the copper alloy of the present embodiment, theelectrical conductivity can be set to 97% IACS or greater, thehalf-softening temperature T_(LD)obtained by performing the tensile testin the direction parallel to the rolling direction can be set to 210° C.or higher, and thus both high electrical conductivity and excellent heatresistance can be achieved.

Further, since the half-softening temperature ratio T_(LD)/T_(TD)calculated from the half-softening temperature T_(LD) obtained byperforming the tensile test in the direction parallel to the rollingdirection and the half-softening temperature T_(TD) obtained byperforming the tensile test in the direction transverse to the rollingdirection is set to be in a range of greater than 0.95 and less than1.08, the anisotropy in heat resistance is small and the strength in ahigh-temperature environment can be sufficiently ensured even in a casewhere the heat resistance is required in both the direction parallel tothe rolling direction and the direction transverse to the rollingdirection, such as a terminal or a bus bar for a high current.

In the present embodiment, in a case where the amount of Ag is set to bein a range of 5 mass ppm or greater and 20 mass ppm or less, Ag issegregated in the vicinity of grain boundaries and grain boundarydiffusion is suppressed by Ag; and thereby, the heat resistance can befurther improved.

Further, in the present embodiment, in a case where the area ratio ofcrystals having a crystal orientation which is 10° or less with respectto Brass orientation {110} <112> is limited to 30% or less, it ispossible to suppress the strength in a direction transverse to therolling direction from being preferentially increased and to reliablysuppress anisotropy in strength.

Further, in the present embodiment, in a case where the strength ratioTS_(TD)/TS_(LD) calculated from the tensile strength TS_(TD) in a caseof performing the tensile test in the direction transverse to therolling direction and the tensile strength TS_(LD) in a case ofperforming the tensile test in the direction parallel to the rollingdirection is set to be in a range of greater than 0.93 and less than1.10, the anisotropy in strength is small and the strength issufficiently ensured even in a case where the strength is required inboth the direction parallel to the rolling direction and the directiontransverse to the rolling direction, such as a terminal or a bus bar fora high current.

Further, in the present embodiment, in a case where the tensile strengthTS_(LD) in the direction parallel to the rolling direction is 200 MPa orgreater, since the tensile strength TS_(LD) in the direction parallel tothe rolling direction is sufficiently high, the copper alloy isparticularly suitable as a material of a component forelectronic/electrical devices, such as a terminal, a bus bar, a leadframe, or a heat dissipation substrate.

Since the plastically-worked copper alloy material according to thepresent embodiment includes the above-described copper alloy, theplastically-worked copper alloy material has excellent electricalconductivity, excellent heat resistance, and small anisotropy in heatresistance, and thus is particularly suitable as a material of acomponent for electronic/electrical devices, such as a terminal, a busbar, a lead frame, or a heat dissipation substrate.

Further, in a case where the plastically-worked copper alloy materialaccording to the present embodiment is a rolled plate having a thicknessof 0.1 mm or greater and 10 mm or less, a component forelectronic/electrical devices, such as a terminal, a bus bar, a leadframe, or a heat dissipation substrate, can be relatively easily moldedby subjecting the plastically-worked copper alloy material (rolledplate) to punching or bending.

Further, in a case where a Sn plating layer or an Ag plating layer isformed on the surface of the plastically-worked copper alloy materialaccording to the present embodiment, the plastically-worked copper alloymaterial is particularly suitable as a material of a component forelectronic/electrical devices, such as a terminal, a lead frame, a busbar, or a heat dissipation substrate.

Further, the component for electronic/electrical devices (such as aterminal, a bus bar, a lead frame, or a heat dissipation substrate)according to the present embodiment includes the above-describedplastically-worked copper alloy material, and thus can exhibit excellentcharacteristics even in a case of being used for high-currentapplications in a high-temperature environment.

In addition, the heat dissipation substrate may be prepared by using theabove-described copper alloy.

Hereinbefore, the copper alloy, the plastically-worked copper alloymaterial, and the component for electronic/electrical devices (such as aterminal, a bus bar, a lead frame, or a heat dissipation substrate)according to the embodiment of the present invention have beendescribed, but the present invention is not limited thereto and can beappropriately changed within a range not departing from the technicalfeatures of the invention.

For example, in the above-described embodiment, the example of themethod for producing the copper alloy (plastically-worked copper alloymaterial) has been described, but the method for producing the copperalloy is not limited to the description of the embodiment, and thecopper alloy may be produced by appropriately selecting a productionmethod of the related art.

EXAMPLES

Hereinafter, results of a verification test conducted to verify theeffects of the present embodiment will be described.

A raw material consisting of pure copper having a purity of 99.999% bymass or greater which had been obtained by a zone melting refiningmethod was charged into a high-purity graphite crucible and subjected tohigh-frequency induction melting in an Ar gas atmosphere furnace.

Abase alloy containing 0.1% by mass of various additive elements wasprepared by using a high-purity copper with 6N (purity of 99.9999% bymass) or greater and a pure metal with 2N (purity of 99% by mass) orgreater. An ingot having the component composition listed in Tables 1and 2 was produced by adding the base alloy to the obtained moltencopper to adjust the component and pouring the molten copper into a heatinsulating material (refractory material) mold. Further, the size of theingot was set such that the thickness was approximately 30 mm, the widthwas approximately 60 mm, and the length was approximately in a range of150 to 200 mm.

The obtained ingot was heated at 900° C. for 1 hour in an Ar gasatmosphere in order to solutionize Mg, and the surface was ground toremove the oxide film, and the ingot was cut into a predetermined size.

Thereafter, the thickness of the ingot was appropriately adjusted toobtain the final thickness, and the ingot was cut. Each of the cutspecimens were subjected to rough rolling under the conditions listed inTables 3 and 4. Next, an intermediate heat treatment was performed underthe condition that the crystal grain size was set to approximately 30 pmby recrystallization.

Next, finish rolling (finish working step) was performed under theconditions listed in Tables 3 and 4.

Next, these specimens were subjected to a mechanical surface treatmentstep by the method listed in Tables 3 and 4.

Further, sandpaper polishing was performed using #180 abrasive paper.

The grinder polishing was performed using a #400 bearing wheel at aspeed of 4500 revolutions per minute.

The shot peening treatment was performed at a projection speed of 10m/sec for a projection time of 10 seconds using a stainless steel shothaving a diameter of 0.3 mm

Thereafter, a finish heat treatment was performed under the conditionslisted in Tables 3 and 4 to produce a strip material having a thicknesslisted in Tables 3 and 4 and a width of approximately 60 mm.

The obtained strip materials were evaluated for the following items.

(Composition Analysis)

A measurement specimen was collected from the obtained ingot, the amountof Mg was measured by inductively coupled plasma atomic emissionspectrophotometry, and the amounts of other elements were measured usinga glow discharge mass spectrometer (GD-MS). Further, the measurement wasperformed at two sites, the center portion of the specimen and the endportion of the specimen in the width direction, and the larger amountwas defined as the amount of the sample. As a result, it was confirmedthat the component compositions were as listed in Tables 1 and 2.

(Brass Orientation Ratio)

The Brass orientation ratio was measured in the following manner byusing a surface transverse to the rolling width direction, that is, atransverse direction (TD) surface as an observation surface with an EBSDmeasuring device and OIM analysis software.

Mechanical polishing was performed using waterproof abrasive paper anddiamond abrasive grains, and finish polishing was performed using acolloidal silica solution. Thereafter, the observation surface wasmeasured in a measurement area of 1 mm² or greater at every measurementinterval of 3 μm at an electron beam acceleration voltage of 20 kV by anEBSD method using an EBSD measuring device (Quanta FEG 450, manufacturedby FEI, OIM Data Collection, manufactured by EDAX/TSL (currentlyAMETEK)) and analysis software (OIM Data Analysis ver. 7.3.1,manufactured by EDAX/TSL (currently AMETEK)). The measured results wereanalyzed by the data analysis software OIM to obtain CI values at eachmeasurement point. The measurement points in which the CI value was 0.1or less were removed, and the orientation of each crystal grain wasanalyzed by the data analysis software OIM. It was determined whether ornot each analysis point had a targeted Brass orientation (within 10°from the ideal orientation), and the Brass orientation ratio (crystalorientation area ratio) in the measurement region was acquired.Specifically, the Brass orientation ratio was the ratio of measurementpoints having a crystal orientation which was in a range of −10° to +10°from the ideal orientation {110} <112> of the Brass orientation amongall the measurement points.

(Electrical Conductivity)

Test pieces having a width of 10 mm and a length of 60 mm were collectedfrom each strip material for characteristic evaluation and the electricresistance was acquired according to a 4 terminal method. Further, thedimension of each test piece was measured using a micrometer and thevolume of the test piece was calculated. Then, the electricalconductivity was calculated from the measured electric resistance valueand volume. Further, the test pieces were collected such that thelongitudinal directions thereof were parallel to the rolling directionof each strip material for characteristic evaluation. The evaluationresults are listed in Tables 3 and 4.

(Strength Ratio)

#13B test pieces specified in JIS Z 2241 were collected from each stripmaterial for characteristic evaluation in a direction parallel to therolling direction and a direction transverse to the rolling direction,and the tensile strength was measured by the offset method in JIS Z2241. The strength ratio TS_(TD)/TS_(LD) was calculated from the tensilestrength TS_(TD) in a case of performing the tensile test in thedirection transverse to the rolling direction and the tensile strengthTS_(LD) in a case of performing the tensile test in the directionparallel to the rolling direction.

The strength ratio TS_(TD)/TS_(LD) and the tensile strength TS_(LD) in acase of performing the tensile test in the direction parallel to therolling direction are listed in Tables 3 and 4.

(Half-Softening Temperature Ratio)

The half-softening temperature was evaluated by obtaining an isochronesoftening curve based on the tensile strength after one hour of the heattreatment in conformity with JCBA T325:2013 of Japan Copper and BrassAssociation. Further, the tensile strength was measured in the samemanner as that for the mechanical characteristics, that is, #13B testpieces specified in JIS Z 2241 were collected, and the tensile strengthwas measured in the direction parallel to the rolling direction and thedirection transverse to the rolling direction by the offset method inJIS Z 2241.

Next, the half-softening temperature obtained above was converted tokelvin, and the half-softening temperature ratio T_(LD)/T_(TD) wascalculated from the half-softening temperature T_(LD) obtained byperforming the tensile test in the direction parallel to the rollingdirection and the half-softening temperature T_(TD) obtained byperforming the tensile test in the direction transverse to the rollingdirection.

The half-softening temperature ratio T_(LD)/T_(TD) and thehalf-softening temperature T_(LD) obtained by performing the tensiletest in the direction parallel to the rolling direction are listed inTables 3 and 4.

TABLE 1 Component composition (mass ratio) Impurities Mg Ag S P Se Te SbBi As [S + P + Se + Te + [Mg]/[S + P + Se + ppm ppm ppm ppm ppm ppm ppmppm ppm Cu Sb + Bi + As] ppm Te + Sb + Bi + As] Invention 1 11 16.0 3.13.1 2.1 2.0 2.1 2.0 2.1 Balance 16.5 0.7 Examples 2 29 19.0 4.5 4.9 2.12.1 2.3 2.3 2.1 Balance 20.3 1.4 3 42 7.0 0.5 0.4 0.2 0.2 0.2 0.2 0.2Balance 1.9 22.1 4 53 22.0 8.0 8.9 2.6 2.4 2.6 2.4 2.4 Balance 29.3 1.85 65 16.0 4.5 4.6 2.1 2.8 2.6 2.6 2.4 Balance 21.6 3.0 6 73 8.0 2.1 1.51.6 1.2 1.3 1.2 1.3 Balance 10.2 7.2 7 81 6.0 0.5 0.4 0.2 0.2 0.2 0.10.1 Balance 1.7 47.6 8 99 17.0 4.5 4.6 3.4 3.6 3.1 3.0 3.2 Balance 25.43.9 9 12 8.0 0.3 0.8 0.8 0.8 0.8 0.8 0.8 Balance 5.1 2.4 10 25 16.0 2.32.2 1.8 1.9 1.7 1.6 1.6 Balance 13.1 1.9 11 39 8.0 2.6 2.6 1.2 1.2 1.01.3 1.3 Balance 11.2 3.5 12 45 10.0 2.1 2.0 0.3 0.3 0.5 0.5 0.6 Balance6.3 7.1 13 51 12.0 0.4 0.4 1.3 1.3 1.3 1.2 1.3 Balance 7.2 7.1 14 67 7.00.5 0.3 0.3 0.3 0.2 0.2 0.2 Balance 2.0 33.5 15 84 9.0 2.1 2.6 1.1 1.01.2 1.2 1.2 Balance 10.4 8.1 16 99 18.0 4.2 4.5 3.5 3.8 3.8 3.7 3.5Balance 27.0 3.7

TABLE 2 Component composition (mass ratio) Impurities Mg Ag S P Se Te SbBi As [S+ P+ Se+ Te + [Mg]/[S + P+ Se + ppm ppm ppm ppm ppm ppm ppm ppmppm Cu Sb + Bi + As] ppm Te + Sb + Bi + As] Invention 17 12 12.0 4.5 4.61.5 1.6 1.4 1.4 1.5 Balance 16.5 0.7 Examples 18 21 16.0 3.6 3.2 2.1 2.52.3 2.3 2.4 Balance 18.4 1.1 19 34 15.0 3.6 3.4 2.4 2.5 2.5 2.6 2.6Balance 19.6 1.7 20 53 24.0 1.3 1.6 0.1 0.2 0.2 0.3 0.3 Balance 4.0 13.421 61 13.0 5.3 5.4 3.1 2.9 2.8 2.8 2.6 Balance 24.9 2.4 22 76 19.0 2.02.2 0.5 0.5 0.5 0.6 0.6 Balance 6.9 11.0 23 81 7.0 0.4 0.4 0.3 0.2 0.20.1 0.1 Balance 1.7 47.6 24 98 19.0 5.6 5.2 2.1 2.5 2.6 2.4 2.6 Balance23.0 4.3 Comparative 1 7 7.0 1.2 1.2 0.7 0.9 0.6 0.6 0.6 Balance 5.8 1.2Example 2 2342 19.0 4.5 4.3 1.2 1.6 1.6 1.5 1.5 Balance 16.2 144.6 3 5918.0 7.1 7.2 3.5 3.6 3.3 3.5 3.2 Balance 31.4 1.9 4 14 12.0 5.4 5.6 3.13.2 3.2 3.4 3.4 Balance 27.3 0.5 5 64 8.0 3.4 3.2 2.1 2.1 2.2 2.0 2.4Balance 17.4 3.7

TABLE 3 Producing step Evaluation Rough Finish Tensile Half- workingworking Mechanical Finish heat treatment Brass Electrical strengthsoftening Rolling Rolling surface Temperature Time Thickness orientationconductivity TS_(TD)/ T_(LD)/ TS_(LD) temperature rate % rate %treatment ° C. sec. mm % % IACS TS_(LD) T_(TD) MPa T_(LD) ° C. Invention1 70 20 Shot peening 390 5 5.0 6.1 99.5 0.97 1.04 258 213 Examplestreatment 2 90 15 Shot peening 250 180000 2.0 3.1 99.0 0.96 1.05 244 245treatment 3 70 30 Shot peening 370 15 5.0 10.0 99.0 0.99 1.02 286 287treatment 4 80 5 Shot peening 250 180000 5.0 0.7 98.8 0.93 1.07 212 324treatment 5 90 70 Shot peening 250 180000 0.1 25.0 97.9 1.07 0.97 378351 treatment 6 90 0 Shot peening 370 15 2.0 0.3 98.7 0.91 1.10 195 210treatment 7 60 20 Shot peening 370 15 8.0 5.7 98.4 0.98 1.04 274 351treatment 8 30 50 Shot peening 390 5 10.0 18.2 98.2 1.03 0.99 334 353treatment 9 90 15 Grinder 370 15 2.0 3.2 99.8 0.95 1.05 247 212polishing 10 40 50 Grinder 250 180000 8.0 18.3 99.4 1.05 0.99 332 249polishing 11 90 60 Grinder 390 5 0.1 22.1 99.1 1.05 0.98 356 298polishing 12 40 40 Grinder — — 10.0 15.2 99.1 1.01 1.00 312 275polishing 13 80 90 Grinder 360 30 0.5 33.4 98.9 1.12 0.93 409 210polishing 14 60 65 Grinder 250 180000 2.0 23.4 98.4 1.06 0.97 368 349polishing 15 50 60 Grinder 350 60 5.0 20.7 97.8 1.05 0.98 357 354polishing 16 90 40 Grinder 390 5 0.5 12.9 97.1 1.01 1.00 310 356polishing T_(LD): half-softening temperature obtained by performingtensile test in direction parallel to rolling direction T_(TD):half-softening temperature obtained by performing tensile test indirection transverse to rolling direction TS_(TD): tensile strength incase of performing tensile test in direction transverse to rollingdirection TS_(LD): tensile strength in case of performing tensile testin direction parallel to rolling direction

TABLE 4 Producing step Evaluation Rough Finish Half- working workingTensile softening Rolling Rolling Mechanical Finish heat treatmentThick- Brass Electrical strength temper- rate rate surface TemperatureTime ness orientation conductivity TS_(TD)/ T_(LD)/ TS_(LD) ature % %treatment ° C. sec. mm % % IACS TS_(LD) T_(TD) MPa T_(LD) ° C. Invention17 40 50 Sandpaper 390 5 8.0 18.4 99.9 1.04 0.99 331 211 Examplespolishing 18 90 60 Sandpaper — — 1.0 20.3 99.4 1.04 0.98 361 221polishing 19 90 20 Sandpaper 360 30 2.0 4.7 99.6 0.98 1.04 259 289polishing 20 80 40 Sandpaper 390 5 2.0 14.8 99.1 1.00 1.00 308 285polishing 21 90 75 Sandpaper 250 180000 0.5 29.0 98.9 1.08 0.97 395 345polishing 22 40 50 Sandpaper 370 15 8.0 15.0 98.5 1.03 0.99 333 358polishing 23 90 10 Sandpaper 350 60 1.0 1.9 98.4 0.94 1.06 239 352polishing 24 60 15 Sandpaper 390 5 10.0 3.5 98.3 0.95 1.05 250 354polishing Comparative 1 90 50 Grinder 360 30 0.5 16.9 99.9 1.03 0.97 329172 Example polishing 2 40 40 Grinder 390 5 8.0 15.1 83.1 1.02 0.99 418412 polishing 3 90 30 Grinder 250 180000 1.0 9.2 98.7 1.00 1.01 287 182polishing 4 50 20 Sandpaper 370 15 10.0 5.7 99.6 0.98 1.04 258 189polishing 5 60 40 — 370 15 0.1 15.1 98.7 0.82 0.84 301 349 T_(LD:)half-softening temperature obtained by performing tensile test indirection parallel to rolling direction T_(TD): half-softeningtemperature obtained by performing tensile test in direction transverseto rolling direction TS_(TD): tensile strength in case of performingtensile test in direction transverse to rolling direction TS_(LD):tensile strength in case of performing tensile test in directionparallel to rolling direction

In Comparative Example 1, since the amount of Mg was less than the rangeof the present embodiment, the half-softening temperature was low, andthe heat resistance was insufficient.

In Comparative Example 2, since the amount of Mg was greater than therange of the present embodiment, the electrical conductivity was low.

In Comparative Example 3, the total amount of S, P, Se, Te, Sb, Bi, andAs was greater than 30 mass ppm, and thus the half-softening temperaturewas low, and the heat resistance was insufficient.

In Comparative Example 4, since the mass ratio [Mg]/[S+P+Se+Te+Sb+Bi+As]was less than 0.6, the half-softening temperature was low, and the heatresistance was insufficient.

In Comparative Example 5, the mechanical surface treatment step was notperformed, the half-softening temperature ratio T_(LD)/T_(TD) was out ofthe range of the present invention, and the anisotropy in heatresistance was increased. Further, the strength ratio TS_(TD)/TS_(LD)was also increased, and the anisotropy in the strength was alsoincreased.

On the contrary, in Invention Examples 1 to 24, it was confirmed thatthe electrical conductivity and the heat resistance were improved in awell-balanced manner, and the anisotropy in heat resistance and strengthwas small.

As described above, according to Invention Examples, it was confirmedthat a copper alloy having high electrical conductivity, excellent heatresistance, and small anisotropy in heat resistance can be provided.

INDUSTRIAL APPLICABILITY

The copper alloy (plastically-worked copper alloy material) of thepresent embodiment is suitably applied to a component forelectronic/electrical devices such as a terminal, a bus bar, a leadframe, or a heat dissipation substrate.

1. A copper alloy comprising: Mg in an amount of greater than 10 massppm and less than 100 mass ppm; and a balance being Cu and inevitableimpurities, wherein the inevitable impurities comprise: S in an amountof 10 mass ppm or less, P in an amount of 10 mass ppm or less, S in anamount of 5 mass ppm or less, Te in an amount of 5 mass ppm or less, Sbin an amount of 5 mass ppm or less, Bi in an amount of 5 mass ppm orless, and As in an amount of 5 mass ppm or less, a total amount of S, P,Se, Te, Sb, Bi, and As is 30 mass ppm or less, and when the amount of Mgis represented as [Mg] and the total amount of S, P, Se, Te, Sb, Bi, andAs is represented as [S+P+Se+Te+Sb+Bi+As], a mass ratio thereof,[Mg]/[S+P+Se+Te+Sb+Bi+As] is 0.6 or greater and 50 or less, anelectrical conductivity is 97% IACS or greater, a half-softeningtemperature ratio T_(LD)/T_(TD) calculated from a half-softeningtemperature T_(LD) obtained by performing a tensile test in a directionparallel to a rolling direction and a half-softening temperature T_(TD)obtained by performing a tensile test in a direction transverse to therolling direction is greater than 0.95 and less than 1.08, and thehalf-softening temperature T_(LD) obtained by performing the tensiletest in a direction parallel to a rolling direction is 210° C. orhigher.
 2. The copper alloy according to claim 1, further comprising: Agin an amount 5 mass ppm or greater and 20 mass ppm or less.
 3. Thecopper alloy according to claim 1, wherein an area ratio of crystalshaving a crystal orientation which is 10° or less with respect to Brassorientation {110} <112> is 30% or less.
 4. The copper alloy according toclaim 1, wherein a strength ratio TS_(TD)/TS_(LD) calculated from atensile strength TS_(TD) in a case of performing a tensile test in thedirection transverse to the rolling direction and a tensile strengthTS_(LD) in a case of performing a tensile test in the direction parallelto the rolling direction is greater than 0.93 and less than 1.10, and atensile strength TS_(LD) in a case of performing a tensile test in thedirection parallel to the rolling direction is 200 MPa or greater.
 5. Aplastically-worked copper alloy material comprising: the copper alloyaccording to claim
 1. 6. The plastically-worked copper alloy materialaccording to claim 5, wherein the plastically-worked copper alloymaterial is a rolled plate having a thickness of 0.1 mm or greater and10 mm or less.
 7. The plastically-worked copper alloy material accordingto claim 5, wherein the plastically-worked copper alloy materialincludes a Sn plating layer or an Ag plating layer on a surface thereof.8. A component for electronic/electrical devices, comprising: theplastically-worked copper alloy material according to claim
 5. 9. Aterminal comprising: the plastically-worked copper alloy materialaccording to claim
 5. 10. A bus bar comprising: the plastically-workedcopper alloy material according to claim
 5. 11. A lead frame comprising:the plastically-worked copper alloy material according to claim
 5. 12. Aheat dissipation substrate which is prepared by using the copper alloyaccording to claim 1.